Wall openings into which window frames or door cases are inserted usually have an inside width which more or less exceeds the outer dimensions of the frame or case, respectively. Therefore, the pre-fabricated case or frame, respectively, has to be adjusted within the wall opening with respect to three orthogonal axes prior to being finally fixedly secured therein. It is known to fixedly secure the frames or cases, respectively, within the wall opening by means of base pieces and/or wedges in accordance with the positional adjustment process. This procedure is cumbersome and time-consuming. Also the removal of the wedges and base pieces after the final securing of the frame or case, respectively, proves to be relatively cumbersome.
It is known to secure cases or frames, respectively, which are adjusted and fixedly secured within the wall opening by means of bolts with elongated shafts, the threaded bolts also forming threaded holes within the side walls of the holes predrilled within the frame whereby the frame is secured at all sides in its relative position by means of the bolts. Prior to the positioning of the bolts a drilling hole is defined within the wall material through means of the drilling holes within the frame. Therefore, the drilling holes within the frame serve as a drilling gauge. If during these mounting operations the frames are not fixedly secured, it may easily happen that they are moved away from their previously position. The consequence is a cumbersome renewed adjustment process.
It is known from EP-A-0 124 832 to engage at least one screw clamp with the frame or case, respectively, for adjusting and securing window frames and door cases. The screw clamp is supported upon a carrying sling which is secured to the wall material by means of an additional screw clamp. It is a disadvantage of this known device that the securing device grips a rear surface of the wall material and therefore can only be utilized for the mounting of frames or cases, respectively, within the so-called wall rabbet type systems. It is a further disadvantage that for a lateral displacement the screw clamp engaged with the frame or case, respectively, initially has to be released. Consequently, a change in the support of the window frame may result which might impair the finished adjustment process. At the least the adjusting operation becomes expensive.